package com.hmdp.utils;

import cn.hutool.core.lang.UUID;
import com.fasterxml.jackson.databind.ser.std.StdKeySerializers;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.data.redis.core.script.RedisScript;

import java.util.Collections;
import java.util.concurrent.TimeUnit;

public class SimpleRedisLock implements ILock{
    private String name;
    private StringRedisTemplate stringRedisTemplate;
    private static final String KEY_PREFIX="lock:";
    private static final String ID_PREFIX= UUID.randomUUID().toString(true)+"-";
    private static final DefaultRedisScript<Long> UNLOCK_SCRIPT;
    //静态代码块初始化加载脚本,如果执行的时候才加载太慢了
    static {
        UNLOCK_SCRIPT=new DefaultRedisScript<>();
        UNLOCK_SCRIPT.setLocation(new ClassPathResource("unlock.lua"));
        UNLOCK_SCRIPT.setResultType(Long.class);
    }
    public SimpleRedisLock(String name, StringRedisTemplate stringRedisTemplate) {
        this.name = name;
        this.stringRedisTemplate = stringRedisTemplate;
    }

    @Override
    public boolean tryLock(long timeoutSec) {
        //获取当前线程标识
        String threadId = ID_PREFIX+Thread.currentThread().getId();
        //获取锁
        Boolean success = stringRedisTemplate.opsForValue().setIfAbsent(KEY_PREFIX + name,threadId , timeoutSec, TimeUnit.SECONDS);
        return Boolean.TRUE.equals(success);
    }

    @Override
    public void unlock() {
        //调用Lua脚本，Redis执行脚本中执行能够1其中操作的保证原子性
        stringRedisTemplate.execute(
                UNLOCK_SCRIPT,
                Collections.singletonList(KEY_PREFIX+name),
                ID_PREFIX+Thread.currentThread().getId());
    }

    /*@Override
    public void unlock() {
        //获取线程标识
        String threadId=ID_PREFIX+Thread.currentThread().getId();
        //获取锁中的标识
        String id = stringRedisTemplate.opsForValue().get(KEY_PREFIX + name);
        //判断标识是否一致
        if(threadId.equals(id)){
            //释放锁
            stringRedisTemplate.delete(KEY_PREFIX+name);
        }
    }*/
}
